A new paper published in Ecological Modelling finds climate sensitivity to doubled CO2 concentrations is significantly lower than estimates from the IPCC and climate models which “utilize uncertain historical data and make various assumptions about forcings.” The author instead uses a ‘minimal model’ with the fewest possible assumptions and least data uncertainty to derive a transient climate sensitivity of only 1.093C:
“A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates.”
Otto et al find equilibrium climate sensitivity [over the next several centuries] is only ~1.3 times greater than transient climate sensitivity, thus the estimate of 1.093C transient sensitivity could be associated with as little as 1.4C equilibrium sensitivity, less than half of the implied IPCC central estimate in AR5 of ~3.3C.
Moreover, this paper does not assume any solar forcing or solar amplification mechanisms. The integral of solar activity plus ocean oscillations explain ~95% of global temperature change over the past 400 years. Including potential solar forcing into the ‘minimal model’ could substantially reduce estimated climate sensitivity to CO2 to a much greater extent.
- Empirical estimates of climate sensitivity are highly uncertain.
- Anthropogenic warming was estimated by signal decomposition.
- Warming and forcing were equated in the time domain to obtain sensitivity.
- Estimated sensitivity is 1.093 °C (transient) and 1.99 °C (equilibrium).
- Empirical study sensitivity estimates fall below those based on GCMs [Global Circulation Models].
Abstract
Climate sensitivity summarizes the net effect of a change in forcing on Earth’s surface temperature. Estimates based on energy balance calculations give generally lower values for sensitivity (< 2 °C per doubling of forcing) than those based on general circulation models, but utilize uncertain historical data and make various assumptions about forcings. A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates.
Jim Cripwell says
I keep on telling you. No-one, and I mean NO-ONE has the slightest idea, because no one can measure climate sensitivity.
Henry says
I just told you that I do know
http://wattsupwiththat.com/2014/07/23/new-paper-finds-transient-climate-sensitivity-to-doubled-co2-levels-is-only-about-1c/#comment-1692933
Why don’t you take your own sample and repeat my test?
Why don’t you just agree with me that climate sensitivity CANNOT be measured?
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Jim, I will agree with you 100%……
We can’t even define climate sensitivity….you would have to do that first
..and measured against what?
Seven Mosher, you write ” You just measure delta T”
How? How do you ensure that any measured Delta T was actually caused by a change in Delta watts? And the change was not caused by some other factor?
Transient Climate Sensitivity (TCR) is defined as the temperature increase at the end of a 70 year period, if CO2 concentration increased 1%/annum, so by the end it doubled (1.01^70 ~ 2).
Now, we do have empirical data for CO2 concentration of the past 55 years. It clearly shows average annual increase was substantially less than that, at about 0.427%. If this rate is extrapolated for the next 70 years, with a TCR of 1.093°C, it implies a further 0.467°C warming by the year 2084, which is 0.067°C/decade.
It is already less than alarming, so no policy whatsoever is needed to curb carbon dioxide emissions.
And that in case we are able to keep up exponential growth of energy generation from carboniferous geofuels for seven more decades, an unlikely scenario. It is far more likely we are forced to switch the bulk of plants to fifth or seventh or whatever generation nuclear, because one ton of ordinary granite, the default stuff continents are made of contains as much useful energy as fifty tons of coal plus 133 tons of atmospheric oxygen.
There is a huge difference between nuclear and nuclear. Instead of the 0.5% fuel efficiency of our current Cold War Plutonium factories we can go for a nearly 100% fuel efficiency, with a hundred times shorter average half life of radioactive isotopes left in waste. Ten thousand times less waste to store in the long run for the same energy output is not much. Also, we need not use high pressure reactor cores, ones at atmospheric pressure are entirely feasible. What is more, once turned off, they would not need active cooling, which increases their safety tremendously.
I can’t see energy shortage ever for the rest of the lifetime of the solar system.
Latitude, you write “Jim, I will agree with you 100%”
Thanks. Now it would be nice to hear from Craig Loehle.
Steven Mosher,
I appreciate that you’ve taken a new approach, today and aren’t speaking in your typical cryptic quasi- aphorisms. However, you’ve told others that if they aren’t a publishing scientist, then there is no room for their voices in the debate. As a result, your posts today constitute a long- winded logical fallacy. For whatever kernel of truth you’ve expressed, more reasons exist to find fault with and work against the dictates inherent in your opinion.
Regards,
Alan
I was unaware that we even have a good, working definition of “climate sensitivity”, much less the ability to measure it. (whatever “it” is)
The majority of the warming post Maunder is due to an increase in solar activity which can be verified by looking at the historical data.
Presently the sun has gone from a very active state up to 2005 to a very quiet state post 2005. This will have climate implications.
Jim Cripwell: I do agree that it is difficult to estimate or compute (not measure) climate sensitivity–but there are ways to get at it. There are many approaches. My paper here merely demonstrates that if you simplify the problem you get a result that is in line with other empirical values (see my paper) and much lower than results based on climate models. I think that result is pretty robust.
This is all a big waste of time.
REPLY: OK, then go waste time somewhere else if you feel that way. – Anthony
Steven Mosher says:
July 23, 2014 at 9:20 am
Goodman
“firstly the world has been warming for several 100 years, clearly there is a long term process independent of AGW.”
Clearly?
hardly.
I love when good skeptics stop examining all their beliefs. the assertions they make are clearly funny.
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So if you can stop examining your beliefs for a minute and explain to me why global temps were dropping in the _residual_ and before AGW?
I don’t think there is any disagreement that it was colder in 1660 then 1900 ( before AGW ) , so what exactly are you objecting to in my statement ?
So far your ASSERTION that there is something wrong with what I said amounts to one word:
“Clearly? hardly.” [ the ‘clearly’ was mine ]
I love it when warmists try to refute a logical argument with a one word assertion and then accuse me of assertion. It’s really funny.
Mosher
I read your overly simplistic instructions on how to get climate sensitivity and then I read the comments by rgbatduke, Don Easterbrook and Dr Norman Page, then I realize you are telling us how to fly a balsa wood toy glider and they are explaining what is required to build & fly a 747. Not in the same league.
“””””…..Steven Mosher says:
July 23, 2014 at 12:09 pm
“OK. HOW do you MEASURE climate sensitivity? No fiddling. Give me the nitty gritty of HOW you measure climate sensitivity.”
Simple.
Start with the definition
Climate sensitivity ( Not sensitivity due to doubling) is defined as
lambda = Change in Temperature/ Change in forcing……””””””
OK, I’ll bite. Just what “Temperature” (measured) is used in this calculation; who measures it, and how ?
And what is the “change in “forcing”, ” that is used in this equation, and where and how is it measured ??
So I’ve heard at least three definitions of climate sensitivity.
First one I recall reading was : “Increase in mean global surface Temperature, for a(ny) doubling of the atmospheric CO2 abundance.
After all, it is change in CO2 that is alleged to give rise to the strictly logarithmic dependence on CO2 abundance, that falls out of the Beer-Lambert Law (they claim). I thought that definition was the claim to fame of the late Stephen Schneider, of Stanford.
Then I heard it was the change in lower troposphere Temperature, rather than surface. The surface is surely the source of the LWIR radiant emissions, due to Temperature. The lower troposphere, being gaseous does not emit any LWIR radiant emissions, as a result of its Temperature (so they also say).
Then it was some LWIR radiant “forcing” in W/m^2 that was supposed to be used instead of CO2, and through some mystery, still retain a logarithmic relation to the Temperature change (any temp change).
Now last time I checked , Temperature and radiant emittance (W/m^2) are supposed to be related by a fourth power law; so how did that become a logarithmic relationship. And since “forcing” is supposed to be a small delta, then the fourth power law, degenerates to a linear one; which also is not logarithmic.
So yes I am mystified; so what are the SI units of “Forcing” and CS ??
Steven Mosher says:
If you want to join the debate. Publish your work .
posting on the internet doesnt count.
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So if I write a paper and publish it in a pay-for-play Indian journal, like BEST did, I’m allowed to enter the debate? Can I also announce my results a year before the paper is peer reviewed and go on a PR tour.
Reg, That’s just harsh! lol
Steven Mosher says:
July 23, 2014 at 12:09 pm
“So while some skeptics join the debate and get published and influence the IPCC…”
Who cares about incremental influence on a corrupt organization focused on a potty hypothesis which has already been discredited to those with any intelligence? The IPCC isn’t going to change its tune until it can no longer carry it in the face of the mounting contradictory evidence, and there is nothing that anyone outside the organization can do to change that.
I do not care to debate epicycles. Nobody whose time is valuable should.
“[P]ersonally, I’ll spend my time being productive. That means answering the change in temperature question as best I can.
Just because you are engaged in an activity does not mean it is a productive activity. Indeed, if you are consuming resources which could better be spent elsewhere, you are decidedly unproductive.
Now the greens down in Venezuela at a UN conference are calling for the end of capitalism as a response to global warming.
It is getting, i think, obvious to almost everyone that there is no catastrophic feedback even the most ardent CAGW groupies are starting to realize it. They will now start to go totally loony and try to create as much havoc as they can to effect “social change” before they move on to something else.
We may quibble about how much CO2 contributes to Climate Change if at all, but as I have explained before the science, while interesting to us, was never that important to the people in the CAGW movement its just a propaganda tool nothing more. I don’t know if they will let it go or not but only time will tell.
sleepingbear dunes: “Not in the same league.”
It’s the Obama syndrome. Although to many of us it was blindingly clear right from the start that he was an empty suit, many otherwise apparently intelligent people paid attention to everything he said for seemingly the longest time.
My theory is there’s a huge variation in peoples’ relative responses to style and substance.. It’s fascinating. We students of human nature never run out of things to learn.
Mosh says:
“Start with the definition
Climate sensitivity ( Not sensitivity due to doubling) is defined as
lambda = Change in Temperature/ Change in forcing
climate sensitivity to doubling c02 is RELATED to this but not the same thing,
lambda = delta Temp / delta Watts”
Well for someone who sets out to “Start with the definition” you have not defined anything.
What “change” ? What is a “delta” if it’s not a change? Temp of what, land, ocean; what depth? Any attempt to relate a power term to temperature implies a heat capacity. SHC of land is about half that of ocean surface. To work out ocean HC you need to define what depth you are considering. Are you talking about a change in average temp or average change in temperature anomaly?
To relate a power term ( change or ‘delta’ rad ) to an energy term ( temp ) you need to be talking about the final equilbrium state, otherwise if it’s instantaneous, you should be comparing dT/dt to rad. or worse a mix of the two.
So if you nave an instantaneous delta Rad at a certain time how do you “measure” the delta T that it produces, separately from the, as yet unfinished temperature changes that are a result of more recent delta Rad.?
These concepts only have meaning inside a model, they are not measurable in a real system.
Of course you could try, as so many less able climatologists have done, to fit a linear regression to a dT / dRad scatter plot. First thing is, that is not a legitimate use of least squares regression and will give you the wrong answer leading to a too high figure for CS, secondly it is not even the correct ratio if you do manage to fit it since it’s an unknown mixture of the in-phase response ( that you are looking for and ) and the orthogonal ( dT/dt ) one that you don’t want. This was pointed out in Spencer and Braswell 2011 and other work by Spencer.
Thats without even considering the way the volcanic forcing has been ‘corrected’ to make climate models work:
http://climategrog.wordpress.com/?attachment_id=884
Steve Mosher says
Steve you need to grow up a little. The people that you are yelling at and that you don’t seem to think matter are the same people who put the pressure on your “ones in power” to listen to people like Anthony. They are the common people who may not have the opportunity to be academics but none the less are very capable of reading something and realizing it is bull, something frankly a lot experts can’t do because the get lost in the minutia of the subject. Many of these people are very good and find flaws in things and noticing fallacy. Those “ones in power” theoretically work for the same people you are ranting at and frankly my friend i don’t feel reading what you write that you are in any position to look down on anyone.
The “ones in power” don’t give a damn about what is right or wrong, good or bad, they only care how they can use it to keep them selves in power. Its the people here who actually care who are the ones who matter.
vukcevic says:
July 23, 2014 at 9:51 am
Leif Svalgaard says: July 23, 2014 at 7:37 am
…………
It was a great loss that von Neumann died in his early 50is, but on the other hand fortunate that a young student (Michael Minovitch) working during his summer vacation at the JPL probably never heard of the Neumann’s advice to Freeman Dyson.
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You are right. There are some great minds out there.
Only last month, I watched a good BBC programme (they do make them occassionally) on Voyager. It was probably a repeat, celebrating that Voyager is now in inter stellar space. It was good to revisit some of the highlights of that grand tour.
Phil. says:
July 23, 2014 at 9:15 am
Salvatore Del Prete says:
July 23, 2014 at 8:33 am
“….”
Not while the earth has been in its current configuration, e.g. no isthmus of Panama. In fact over the last 800,000 years there’s no evidence of 300ppm being exceeded.
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And yet we know that the Holocene Optimum was many degrees warmer than today (probably with an ice free Arctic),
We also know that the Minoan, Roman and Viking Warm Period (at least in the Northern Hemishere; there being no reliable data for the Southern Hemisphere so we do not know what the SH was like, but we know of no process whereby it would be significantly out of step with the NH) were some 1 to 2 degrees warmer than today, with Greenland and Northern Europe more generally (since we are finding similar archaeological evidence in Norway from glacier retreat) must have been 3 to 5 degrees warmer than today to enable farming settlements to exist where there are still glaciers today, and all this was achieved with CO2 not exceeding 300ppm!!
Natural Variation (whatever that encompasses) quite obviously has a large band, and can drive temperatures far higher than we observe today, and for that reason alone, we cannot rule out Natural Variation as being wholly responsible for the temperature trends measured these past 150 or so years..
This is nonsense we dont even know if thre is ANY real worl atmospheric C02 +sensitivity y might be -negative for all we know. (Negative feed backs) Most of those graphs shown at the 9ICCC show C02 at 1000’s ppm during ice ages. This is again feeding the warmist trolls theory, but go ahead it really does not matter any more
Bill Illis says:
July 23, 2014 at 12:07 pm
The following charts are the historic CO2 sensitivity over the last 10,000 years, 200,000 years, 5 million years, 25 million years, 50 million years and 750 million years.
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Your charts are interesting, and onviously much work has gone into them, but they are not “the historic C02 sensitivity”.
As you note there is huge variability. Further
1). It is not known why the past temperatures were warm and to what extent this was due to natural variability rather than CO2; and
2). Whether the CO2 measured was a response to the then current temperatures, as opposed to the driver of those temperatures.
Until one can identify natural variation, and fully eliminate it from the observational data, one does not get a CO2/temp signal.
Even when you get such signal, you need to ascertain which is the horse, and which is the cart. There is considerable evidence that suggests that CO2 lags temperature at all time scales, and, if this is right, it is therefore the cart.
I find it difficult to see why noone has taken the opportunity to do an experiment using a 1 to several km long cylinder isolated in a vacuum and measure infra red spectral transmision at various CO2 concentrations as a function of distance instead of just lab measurements done over the cm scale. You would think the idea had occured to someone. Then just maybe we could talk data instead of squabbling. Guess I will have to do it myself?
So Mosher, how exactly do we measure delta T? As soon as you start gridding you are no longer measuring, you are modeling.
How do we measure forcing?
How do we then attribute changes to T (assuming we can measure it) to changes in forcing (assuming we can measure it) with any certainty? At best we simply note they have coincided.
I’m not sure you have actually thought any of this through despite your attitude.
The illustrious rgb has it 100% correct.